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Probabilistic modelling of deterioration of reinforced concrete structures
No full textInternational audienceReinforced concrete (RC) structures deteriorate over time which affects their strength and serviceability. To develop measures for protecting new RC structures against deterioration and assess the condition of existing RC structures subjected to deterioration an understanding of the deterioration processes and the ability to predict their development, including structural consequences, are essential. This problem has attracted significant attention from researchers, including those working in the area of structural reliability (in particular within the JCSS) since there are major uncertainties associated with the deterioration processes and their structural effects. The paper presents an overview of the probabilistic modelling of various deterioration processes affecting RC structures such as corrosion of reinforcing steel, freezing-thawing, alkali-aggregate reaction, sulphate attack and fatigue, and their structural implications, including the historical perspective and current state-of-the-art. It also addresses the issues related to the inspection/monitoring of deteriorating RC structures and the analysis of collected data taking into account relevant uncertainties. Examples illustrating the application of the presented probabilistic models are provided. Finally, the current gaps in the knowledge related to the problem, which require further attention, are discussed
Deciphering tidal signature in a fluvial-dominated delta using digital outcrop models (Roda Sandstone, Eocene, South Pyrenean Basin)
No full textDeltaic environments are crucial depositional systems for georesources, often studied for their excellent reservoir quality in both ancient and modern contexts. However, while mixed river tide-influenced deltas are complex and important, they remain underexplored in the ancient sedimentary record. This study focuses on the Roda Sandstone, a Lower Eocene fluvial-dominated, tide-influenced delta system in the Graus-Tremp foreland basin, to address gaps in understanding the interaction between fluvial and tidal processes within these environments. Fieldwork and core analysis were conducted to investigate the Roda Sandstone. Nineteen sedimentological sections were logged, and palaeocurrents were measured in the field. A Digital Outcrop Model (DOM) was created using 11,000 drone-captured images, georeferenced with DGPS data. The Digital Outcrop Model was processed with photogrammetry and analysed using a specialised for detailed stratigraphic and facies interpretation. Additionally, five well cores, totalling 340 m, were described and integrated with the Digital Outcrop Model. The sedimentological and stratigraphic study combined with the Digital Outcrop Model interpretation led to the identification of 10 facies grouped into five facies associations and the recognising of 7 deltaic lobes, representative of fifth-order sequences. The 3D evolution of these lobes reveals variations in progradation directions and the intensity of tidal reworking. This shows a gradual shift to a tidally dominated-deflected delta front as they were prograde. This work enabled the characterization of tidal sedimentary bodies, including the dimensions of tidal dunes and bars, paleo-bathymetries, and their specific locations within both progradational and retrogradational sequences. During regressive periods, the preservation of tidal dunes and bars intercalated in the delta foresets depends on the fluvial sediment supply and autocyclic factors. Whereas the preservation of larger tidal bars on bottomsets is permitted by the lower river sediment supply during transgressive periods of fourth-order cycles. This research advances our understanding of ancient mixed deltas by providing a depositional model that clarifies the preservation of tidal features. Additionally, it underscores the value of DOMs in enhancing correlations, distinguishing different sedimentary structures generated by competing currents, and offering detailed facies mapping for improved paleoenvironmental interpretations.</div
Using programmable infusion pump in avian species – a validation methodology in geese
No full textInternational audienceWildlife face anthropogenic and natural stressors that affect their physiology and behaviour. The activity of the hypothalamic–pituitary–adrenal axis and glucocorticoid (GC) production is intrinsically linked with energy regulation and environmental stressors. Understanding the physiological mechanisms behind animals' decisions requires experiments that manipulate GC levels and measure behavioural or life‐history outcomes. Current phenotypic engineering experiments lack the ability to deliver hormones in a pulsatile or circadian manner, limiting our ability to mimic chronic stress or isolate the effects of capture and handling from GC manipulation. We developed a method to externally attach commercial programmable infusion pumps (iPrecio SMP‐200) to birds to deliver hormones subcutaneously at pre‐programmed rates. We tested this method on five semi‐captive Canada geese Branta canadensis and five greater snow geese Anser caerulescens atlanticus , monitoring changes in body mass, wound healing, and the operational state of the pumps. In snow geese, we conducted a hormonal experiment by delivering adrenocorticotropic hormone (ACTH) via the pumps to stimulate GC production. We then measured body mass at three time points, recorded activity using dynamic body acceleration, and collected fecal samples daily to assess corticosterone levels (the main GC in birds). Pumps were deployed for 11 to 14 days, with 7 out of 10 remaining functional throughout. One bird showed minor inflammation, but no apparent adverse effects on body mass or activity were observed. ACTH delivery led to significant increases in fecal corticosterone levels and dynamic body acceleration. This study represents the first successful external use of iPrecio pumps in birds and provides a promising tool for investigating circadian hormone dynamics, chronic stress, and ecotoxicology in wild species under more natural conditions
Les braies au cordelier - Édité d'après le ms. BnF fr. 19152
No full textLes braies au cordelier - Édité d'après le ms. BnF fr. 1915
La protection des populations contre les risques liés aux PFAS : un défi juridique ?
No full textInternational audienceLes PFAS, substances persistantes et potentiellement dangereuses sont largement utilisés dans de nombreux produits d’usage courant. Ces substances d’une grande stabilité chimique, sont non dégradables. Il existe des milliers de molécules différentes dont les effets sont mal connus. Le droit international, européen et interne tente de les réglementer mais de manière assez fragmentée. La France vient notamment d’adopter le 27 février 2025 une loi visant à protéger la population des risques liés à ces substances désignées aussi comme des polluants éternels. Compte tenu du caractère massif de la contamination à l’échelle mondiale, du manque d’information et donc de la difficulté de limiter leurs impacts, une réflexion plus large s’impose pour élever l’ambition du droit applicable en s’appuyant sur une approche intégrée et transversale. Dans cette perspective, l’approche One health, développée au niveau international semble s’imposer
Les TAAF : des territoires singuliers pour un appel à la prospective juridique
No full textInternational audienceCe chapitre présente les conclusions du colloque. Il permet d’aborder non seulement les singularités et les enjeux des TAAF mais aussi d’ouvrir une réflexion plus approfondie sur des aspects éthiques de la recherche, sur des questionnements fondamentaux relatifs à la mise en œuvre du droit interne articulé avec le droit européen et le droit international. Il conduit à repenser différents aspects de la mise en œuvre du droit de l’environnement notamment sur le plan de ces principes et de ses instruments.Ces territoires, géographiquement si éloignés de la métropole française, nous rapprochent certainement de la bonne compréhension des enjeux environnementaux dans une approche pluridisciplinaire ouverte sur le monde avec pour conséquence une prise de conscience de nos responsabilités en tant que scientifiques, en tant qu’acteurs de la protection de ces territoires et, pour l’Etat français, en tant que porteur de solutions innovantes et adaptées en prise avec une coopération environnemental internationale renforcée
Are we overestimating the benefits of agricultural intensification by overlooking nature-based alternatives?
No full textAgriculture relies heavily on anthropogenic inputs, but reducing their use is critical to reduce the negative impact on ecosystems, —on which production ultimately depends. At the same time, reducing inputs is often viewed as risky and potentially costly for farmers, which implicitly assumes that inputs are already being used in optimal way. However, conventional estimations of allocative efficiency – optimal use of inputs - are subject to several biases, which obscures the understanding of what is an optimal input allocation. In this short communication, we highlight what we consider a critical but often overlooked bias: the failure to account for nature-based alternatives to human-made inputs. We explore this issue through microeconomic theory and econometrics, and highlight that accounting for nature-based solutions may lead to a reconsideration of how the efficiency of certain anthropogenic inputs is understood. We illustrate this using a bioeconomic model of oilseed rape production, where farmers can manage pests either through chemical inputs or nature-based solutions, such as grassland re-implementation to enhance natural pest control. Our results show that both the productivity and allocative efficiency of insecticides are overestimated when the potential for farmers to rely on nature-based solutions is excluded from the analysis. This study contributes by showing that neglecting ecosystem services as a viable and competitive alternative to human-made production inputs generates a deadweight loss for society. Rather than focusing solely on negative externalities—as is often the case—our approach shifts the perspective toward identifying what constitutes the economically efficient way to manage agricultural systems
Are the Kids Alright? Dehydration and High Temperatures During Pregnancy Impact Offspring Physiology, Morphology, and Survival in a Cold-adapted Lizard
No full textFrom the symposium “Identifying the physiological mechanisms that underlie phenotypic responses to rapid environmental chang e” presented at the annual meeting of the Society for In tegrative and Comparative Biology, January 3–6, 2024 Atlanta, Georgia.International audienceClimate change will continue to increase mean global temperatures, with daily minima increasing more than daily maxima temperatures on average. In addition, altered rainfall patterns due to climate change will disrupt water availability. Such changes are likely to influence thermo-hydroregulation and reproduction strategies in terrestrial ectotherms. We manipulated access to preferred diurnal temperature (9 h vs. 4 h at preferred temperature), nocturnal temperature at rest (22 vs. 17°C) as well as water availability during gestation (± ad libitum access to water) in female common lizards (Zootoca vivipara), a cold- and wet-adapted species. We previously reported that hot conditions (day and night) accelerated gestation but high nighttime temperatures increased the burden on females already constrained by heavy resource and water investment during gestation. We expanded the understanding of this relationship by examining the effects of maternal hydration and temperature on offspring (neonates and juveniles; N = 625) physiology (water loss rates and respiratory activity), morphology, performance (endurance capacity and growth), and survival. On average, longer access to preferred temperature during the day conferred benefits on offspring growth and survival, despite a negative effect on body condition at birth. High nighttime temperatures during gestation reduced offspring postnatal growth during early life and, together with high daytime temperatures, reduced tail width and endurance capacity at birth as well as offspring survival. Additionally, water deprivation poses a challenge to homeostasis, but offspring demonstrate resilience in coping with this potential stressor and these effects were not stronger in hot climates. Notably, the benefits of hotter environments are not always additive, highlighting the complexity of temperature-mediated effects on maternal and offspring outcomes
Wind turbine threats to bustards: spatially explicit risk modelling from empirical data
No full textInternational audienceWind energy is considered a renewable alternative to fossil fuels, but with the increasing development of wind farms, the threat to birds is a growing concern. Flight height is a critical behaviour trait when assessing risk with wind turbines, as it can affect both collision risk and avoidance behaviour. This study used 12 years of GPS data collected on the little bustard, to assess the potential risk of wind farms during breeding or migration. Long-term demographic data are unavailable for this species, and collision-mortality data largely absent. We thus estimated mortality by evaluating collision risk with wind turbines through flight behaviour characteristics. Using a dataset of 8,891,945 GPS fixes, we found that during breeding season, little bustards spent 0.8 % of their time flying, with males flying about twice as much as females. Maximal flight activity was at twilight, especially for females. 18-60 % of all flights were at a height within the range of blades: more at night and more in females than in males. Using the explicit spatial distribution of both bustards and wind turbines in the study region, we estimated mortality risk to be above 1 % per year, i.e. an increase in the adult mortality rate of about 10 %. This increased mortality seems unsustainable for this endangered population. Our method of explicit risk calculation could be transferred to any large-sized species for which GPS data of flight activity is available. We recommend avoiding the development of further turbines within 2000 m of any current male location
Regional innovation ecosystems to support sustainable forest landscape futures
No full textInternational audienceInnovation in forest and landscape management is necessary to address escalating stresses on ecosystems, advance Indigenous peoples' self-determination, support shifts towards circular bio-economies and realise regional value creation opportunities. In this study we identify barriers and challenges to regional forest innovation in the Gippsland region of Victoria, Australia. Using key informant interviews and survey research we assess the extent to which innovation actors are working together, sharing information, and fostering the communicative relationships needed to support collective innovation. We find a lack of suitable innovation architecture (frameworks and structures) to support collective ideation, learning, and exchange. We then identify opportunities for regional innovation ecosystem thinking to inform future forest landscape strategies. Specifically, there is a need for government agencies to rebalance power relations among actors and to place greater emphasis on the development of innovation niches to unlock place-based entrepreneurial discovery processes and encourage emergent leadership to leverage existing regional capacities